U.S. patent number 6,692,064 [Application Number 10/049,383] was granted by the patent office on 2004-02-17 for reinforced blow-molded bumpers.
This patent grant is currently assigned to Conix Corporation. Invention is credited to Marshall Ray Porter.
United States Patent |
6,692,064 |
Porter |
February 17, 2004 |
Reinforced blow-molded bumpers
Abstract
The present invention provides a blow-molded vehicle part and a
blow-molding process for generating a one-piece vehicle part with
improved strength, aesthetic appearance and reduced weight and
cost. The blow-molded vehicle part includes a front vehicle part
portion and a back vehicle part portion, wherein the front vehicle
part and the back vehicle part have at least an outer unreinforced
layer of a thermoplastic that forms a smooth outer surface of the
vehicle part and a reinforced inner layer.
Inventors: |
Porter; Marshall Ray (Oakdale,
IL) |
Assignee: |
Conix Corporation
(CA)
|
Family
ID: |
31190490 |
Appl.
No.: |
10/049,383 |
Filed: |
February 11, 2002 |
PCT
Filed: |
August 09, 2000 |
PCT No.: |
PCT/US00/21621 |
PCT
Pub. No.: |
WO01/12407 |
PCT
Pub. Date: |
February 22, 2001 |
Current U.S.
Class: |
296/187.01;
264/510; 264/512; 293/102; 293/120; 296/146.1; 296/146.8;
296/50 |
Current CPC
Class: |
B60R
19/18 (20130101); B60R 2019/184 (20130101); B60R
2019/1853 (20130101) |
Current International
Class: |
B60R
19/18 (20060101); B60R 027/00 () |
Field of
Search: |
;293/102,110,120,122
;264/510,512 ;296/187.01,50,146.1,146.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Pape; Joseph D.
Assistant Examiner: Coletta; Lori L.
Attorney, Agent or Firm: Banner & Witcoff, Ltd
Parent Case Text
This application is a 371 of PCT/US00/21621 Aug. 9, 2000 which
claims the benefit of provisional application 60/148,889 filed Aug.
13, 1999.
Claims
What is claimed is:
1. A blow-molded vehicle part comprising: a front vehicle part
portion, and a back vehicle part portion, the front vehicle part
and the back vehicle part having an outer unreinforced layer of a
thermoplastic that forms a smooth outer surface of the vehicle part
and a reinforced inner layer lying against the outer unreinforced
layer the reinforced inner layer including at least one of: glass,
mineral, carbon fibers, glass microspheres, ceramic microspheres
and nano-particles, the back vehicle part portion including a
recessed portion that is recessed toward the front vehicle part
portion to form a gap space between the front vehicle part portion
and the recessed portion, wherein the recessed portion with the gap
space is formed during a molding process, the front vehicle part
portion and the back vehicle part portion further including another
layer of unreinforced thermoplastic that sandwiches the reinforced
inner layer between the outer unreinforced layer and said other
layer of unreinforced thermoplastic.
2. The blow-molded vehicle part of claim 1 wherein: the back
vehicle part portion is recessed toward the front vehicle part
portion to form a distance between the front vehicle part portion
and the recessed portion that is less than a thickness of parison
layers that line the mold, bonding said other layer of unreinforced
thermoplastic of the back vehicle part portion with said layer of
unreinforced thermoplastic of the front vehicle part portion during
a molding process.
3. The blow-molded vehicle part of claim 1 wherein the vehicle is
an automobile.
4. The blow-molded vehicle part of claim 1 wherein the part is one
of: a bumper, a tail-gate, a door, and a running board.
5. A blow-molding process for manufacturing a multilayered portion
vehicle part comprising the steps of: extruding a multilayered
thermoplastic parison to a length suitable for a size of a
preselected mold, wherein at least one reinforced inner layer
includes at least one of: glass, mineral, carbon fibers, glass
microspheres, ceramic microspheres and nano-particles and wherein
the reinforced inner layer is sandwiched between an outer
unreinforced layer and an inner unreinforced layer; closing the
preselected mold around the parison; heating the parison to a
temperature at which the parison is very soft but still able to
retain a desired shape; injecting a high pressure gas into the
parison to expand the parison against an inside of the preselected
mold; and allowing the parison to-cool and, when the thermoplastic
material has cooled sufficiently, removing the part from the
preselected mold.
6. The blow-molding process of claim 5 further including, before
removing the part from the preselected mold, repeating the above
steps at least one time using an unreinforced thermoplastic
material until a desired number of layers are formed.
7. The blow-molding process of claim 5 wherein the vehicle is an
automobile.
8. The blow-molding process of claim 5 wherein the part is one of:
a bumper, a tail-gate, a door, and a running board.
9. The blow-molding process of claim 5 further including, before
removing the part from the preselected mold, repeating the above
steps at least one time using a reinforced thermoplastic material
until a desired number of layers are formed.
10. The blow-molding process of claim 5, the step of injecting a
high pressure gas into the parison to expand the parison against an
inside surface of the preselected mold a back vehicle part portion
is recessed toward a front vehicle part portion to form a distance
between the front vehicle part portion and the recessed portion
that is less than a thickness of parison layers that line the mold,
and the further step of bonding an innermost layer of the back
vehicle part portion with an innermost layer of the front vehicle
part portion.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to processes for
blow-molding and to articles made by blow-molding. More
particularly, the present invention relates to multi-layer
blow-molded bumper structures that incorporate reinforcing
materials.
State-of-the-art automobile bumpers are typically manufactured by
molding thermoplastics using a variety of molding techniques. These
techniques strive to provide the best aesthetic qualities and
structural strength, while reducing the material costs and weight
of the finished product. Many techniques and bumper structures
utilize reinforcing materials, such as glass fibers in order to
increase the structural strength and reduce weight. While the use
of such reinforcing materials is known to provide many desirable
characteristics to molded articles, the use of such reinforcing
materials in bumper structures produced by blow-molding techniques
has heretofore been problematic. One reason for this is that the
use of reinforcing materials in blow-molded bumper structures may
produce irregularities or read-through in the outer surface finish
of the bumper. Another reason is that the presence of many
conventional reinforcing materials such as fiber reinforcement may
render the bumper surface finish brittle and therefore unable to
resist cracking when the bumper is subject to mild
deformations.
In addition to the use of reinforcing materials, another known
technique for increasing the strength of bumper structures involves
the use of tacked-off bumper structures. In such structures, the
internal surfaces of a bumper are made to contact and bond with
each other to add structural strength. Typically, however,
tacked-off structures result in a thermal sink and read-through to
the finished surface. As such, tacked off structures have
heretofore required the addition of a separately molded cover to
provide an aesthetically pleasing exterior surface.
It would be desirable to provide blow-molded bumper structures
which addresses the aforementioned shortcomings in the prior art.
Specifically, it would be desirable to provide blow-molded bumper
structures that utilize reinforcing materials, such as glass,
mineral or carbon fibers or glass microspheres or nano-particles
and which exhibit suitable surface finishes, even in bumper
structures that incorporate tacked-off structures.
SUMMARY OF THE INVENTION
The aforementioned problems are eliminated and the desired
advantages are realized by the present invention, which provides a
blow-molded bumper structure that incorporates one or more internal
layers that are reinforced with reinforcing materials, such as
glass, mineral or carbon fibers or glass microspheres or
nano-particles. The reinforced layer increases the strength of the
bumper while reducing weight, density and material costs. The
reinforced layer also provides a thermal barrier that acts to
prevent read-through in tacked-off structures.
In one aspect, the invention may be defined as a blow-molded bumper
including at least one inner layer containing a reinforcing
material. More particularly, the invention may be defined as the
aforementioned blow-molded bumper, wherein the reinforced layer is
provided with glass fibers, mineral fibers, carbon fibers or glass
microspheres or nano-particles.
In another aspect, the invention may be defined as a multi-layer
blow-molded automobile bumper that includes at least one reinforced
layer sandwiched between two unreinforced layers. More
particularly, the invention may be defined as the aforementioned
bumper, wherein the reinforced layer is provided with glass fibers,
ceramic microspheres, mineral fibers, carbon fibers or glass
microspheres or nano-particles.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings which arc incorporated into and form a
part of the specification, illustrate embodiments of the present
invention and, together with the description, serve to explain the
principles of the invention. The drawings are only for the purpose
of illustrating preferred embodiments of the invention and are not
to be construed as limiting.
FIG. 1 is a cross-sectional view of a two-layered blow-molded
automobile bumper including an inner reinforced layer;
FIG. 2 is a cross-sectional view of a three-layer blow-molded
automobile bumper;
FIG. 3 is a cross-sectional view of a three-layer blow-molded
automobile bumper; and
FIG. 4 is a cross-sectional view of a vehicle bumper manufactured
in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a cross-sectional view of a blow-molded automobile bumper
100 according to a preferred embodiment of the present invention.
Bumper 100 includes a front portion 102 and back portion 104. An
outer layer 106 is provided as an unreinforced layer of
thermoplastic which has desirable aesthetic qualities so as to form
a smooth outer surface. Outer layer 106 completely surrounds an
inner layer 110, which is provided as a reinforced thermoplastic.
According to the invention, glass, mineral, carbon fibers, glass
microspheres, ceramic microspheres or nano-particles may be used
separately or in combination to provide the reinforcement to the
reinforced inner layer 110. The glass may be in the form of glass
fibers or glass microspheres. The mineral is typically in the form
of mineral fibers. The bumper 100 shown in FIG. 1 includes a gap
space 112 between the front portion 102 and a recessed portion 114,
which is formed during the molding process. Clearly the method of
the present invention may be used to manufacture, for example, a
bumper, a tail-gate, a door, or a running board.
As will be recognized by those of ordinary skill in the art, the
bumper 100 depicted in FIG. 1, may be manufactured by utilizing a
multilayered extrusion blow molding process. The first step is the
extrusion of the multilayered thermoplastic parison to a length
suitable for the size of the mold, wherein at least one inner layer
includes at least one of: glass, mineral, carbon fibers, glass
microspheres, ceramic microspheres or nano-particles. The parison
is formed by heating thermoplastic material to a temperature where
it is very soft but still able to retain its shape. Second, the
mold is closed around the parison. High pressure gas is injected
into the parison expanding it against the inside of the mold.
Contact with the mold cools the material until hard. Finally the
mold is opened and the molded part is removed using appropriate
equipment. This process is the same regardless of how many layers
are in the parison.
FIG. 2 illustrates a three-layer bumper 200 according to the
invention. The bumper structure 200 includes a reinforced barrier
layer 202 that is sandwiched between an outer layer 204 and an
inner layer 206. As in the example of FIG. 1, reinforced barrier
layer 202 may include glass, mineral, carbon fibers, glass
microspheres, ceramic microspheres or nano-particles, for examples.
This particular structure, with the reinforced barrier layer 202
sandwiched between two layers of unreinforced material is useful to
prevent the separation of layers upon deformation of the bumper
structure.
FIG. 3 illustrates another three-layer bumper structure 300
according to the invention. The bumper structure is like that shown
in FIG. 2, except that it includes a tacked-off portion 310 where
an internal surface 312 of the front portion 314 and an internal
surface 316 of the recessed portion 318 are caused to bond
together. Tack-off 310 between the front portion 314 and back
portion 340 can be controlled by designing the distance in the
specified area to be less than the thickness of the parison layers
that line the mold.
As will be appreciated by those of ordinary skill in the art, the
thermal insulating characteristics of the reinforced barrier layer
302, owing to the presence of glass, mineral, carbon fibers, glass
micropheres, ceramic microspheres or nano-particles, acts to
prevent read-through of the tacked-off portion to the outer surface
330 of the front portion 314. Thus, the blow-molded bumper 300 may
be formed in a single step without the addition of an outer surface
layer to conceal read-through. Moreover, the tacked-off portion
provides increased structural strength to the bumper 300.
The fiber-reinforced layer of the invention provides for reduced
material cost, since the fibers therein act as a relatively
inexpensive filler material to the relatively expensive
thermoplastic materials. Thus, the fiber reinforced layer creates
cost savings due to the displacement of comparatively heavy and
costly resin materials with comparatively inexpensive reinforcing
materials or nano-particles. The result is a blow-molded, one-piece
automobile bumper, with improved strength, aesthetic appearance and
reduced weight and cost compared to previous bumpers.
FIG. 4 is a cross-sectional view of a vehicle bumper 402
manufactured in accordance with the present invention.
Although the preferred embodiments of the invention have been
described hereinabove in some detail, it should be appreciated that
a variety of embodiments will be readily available to persons
utilizing the invention for a specific end use. The description of
this invention is not intended to be limiting on this invention,
but is merely illustrative of the preferred embodiment of this
invention. Other products and methods that incorporate
modifications or changes to that which has been described herein
are equally included within this application. Additional objects,
features and advantages of the present invention will become
apparent by referring to the above description of the invention in
connection with the accompanying drawings.
* * * * *